bd119c6923
Disintegrate asm/system.h for Tile. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Chris Metcalf <cmetcalf@tilera.com>
148 lines
4.2 KiB
C
148 lines
4.2 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#ifndef _ASM_TILE_BARRIER_H
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#define _ASM_TILE_BARRIER_H
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#include <arch/chip.h>
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#include <arch/spr_def.h>
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#include <asm/timex.h>
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/*
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* read_barrier_depends - Flush all pending reads that subsequents reads
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* depend on.
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*
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* No data-dependent reads from memory-like regions are ever reordered
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* over this barrier. All reads preceding this primitive are guaranteed
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* to access memory (but not necessarily other CPUs' caches) before any
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* reads following this primitive that depend on the data return by
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* any of the preceding reads. This primitive is much lighter weight than
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* rmb() on most CPUs, and is never heavier weight than is
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* rmb().
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*
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* These ordering constraints are respected by both the local CPU
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* and the compiler.
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*
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* Ordering is not guaranteed by anything other than these primitives,
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* not even by data dependencies. See the documentation for
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* memory_barrier() for examples and URLs to more information.
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*
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* For example, the following code would force ordering (the initial
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* value of "a" is zero, "b" is one, and "p" is "&a"):
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*
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* <programlisting>
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* CPU 0 CPU 1
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*
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* b = 2;
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* memory_barrier();
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* p = &b; q = p;
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* read_barrier_depends();
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* d = *q;
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* </programlisting>
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*
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* because the read of "*q" depends on the read of "p" and these
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* two reads are separated by a read_barrier_depends(). However,
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* the following code, with the same initial values for "a" and "b":
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*
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* <programlisting>
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* CPU 0 CPU 1
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*
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* a = 2;
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* memory_barrier();
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* b = 3; y = b;
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* read_barrier_depends();
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* x = a;
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* </programlisting>
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*
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* does not enforce ordering, since there is no data dependency between
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* the read of "a" and the read of "b". Therefore, on some CPUs, such
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* as Alpha, "y" could be set to 3 and "x" to 0. Use rmb()
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* in cases like this where there are no data dependencies.
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*/
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#define read_barrier_depends() do { } while (0)
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#define __sync() __insn_mf()
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#if !CHIP_HAS_MF_WAITS_FOR_VICTIMS()
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#include <hv/syscall_public.h>
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/*
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* Issue an uncacheable load to each memory controller, then
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* wait until those loads have completed.
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*/
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static inline void __mb_incoherent(void)
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{
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long clobber_r10;
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asm volatile("swint2"
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: "=R10" (clobber_r10)
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: "R10" (HV_SYS_fence_incoherent)
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: "r0", "r1", "r2", "r3", "r4",
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"r5", "r6", "r7", "r8", "r9",
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"r11", "r12", "r13", "r14",
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"r15", "r16", "r17", "r18", "r19",
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"r20", "r21", "r22", "r23", "r24",
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"r25", "r26", "r27", "r28", "r29");
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}
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#endif
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/* Fence to guarantee visibility of stores to incoherent memory. */
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static inline void
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mb_incoherent(void)
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{
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__insn_mf();
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#if !CHIP_HAS_MF_WAITS_FOR_VICTIMS()
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{
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#if CHIP_HAS_TILE_WRITE_PENDING()
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const unsigned long WRITE_TIMEOUT_CYCLES = 400;
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unsigned long start = get_cycles_low();
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do {
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if (__insn_mfspr(SPR_TILE_WRITE_PENDING) == 0)
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return;
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} while ((get_cycles_low() - start) < WRITE_TIMEOUT_CYCLES);
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#endif /* CHIP_HAS_TILE_WRITE_PENDING() */
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(void) __mb_incoherent();
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}
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#endif /* CHIP_HAS_MF_WAITS_FOR_VICTIMS() */
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}
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#define fast_wmb() __sync()
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#define fast_rmb() __sync()
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#define fast_mb() __sync()
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#define fast_iob() mb_incoherent()
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#define wmb() fast_wmb()
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#define rmb() fast_rmb()
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#define mb() fast_mb()
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#define iob() fast_iob()
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#ifdef CONFIG_SMP
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#define smp_mb() mb()
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#define smp_rmb() rmb()
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#define smp_wmb() wmb()
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#define smp_read_barrier_depends() read_barrier_depends()
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#else
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#define smp_mb() barrier()
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#define smp_rmb() barrier()
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#define smp_wmb() barrier()
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#define smp_read_barrier_depends() do { } while (0)
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#endif
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#define set_mb(var, value) \
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do { var = value; mb(); } while (0)
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_TILE_BARRIER_H */
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